The fighting in Yemen continued this week, escalating what many view as a proxy war between Saudi Arabia and Iran. A group of Shia rebels, known as the Houthis and backed by Iran, continued to advance in Yemen. At the same time, Saudi Arabia continued to lead a military coalition of Arab states, deploying massive airstrikes for nine nights in a row. The Saudis want to restore Yemen's president to power. The Houthis, though, captured a presidential palace in the strategic sourthern porty city of Aden, in addition to killing a Saudi soldier and wounding five others in a skirmish at the Yemeni border.

As this episode explores, the fighting between Saudi Arabia and Iran in Yemen of today is just the latest chapter in the tense, often violent, relationship between the two countries. In 1929, the future looked relatively peaceful for the two countries, symbolized by the signed "Saudi-Iranian Friendship Treaty". However, the counties began evolving in different ways, as Iran's leader of the time, the Shah, pushed the country toward westernization. Saudi Arabia, on the other hand, found itself on a more conservative path. In addition, the countries are largely split on their predominant sects of Islam. Saudis follow Wahhabism, a very conservative sect of the Sunni faith, while Iranians are largely "Twelvers" of the Shia faith. To this day, the two countries jockey for influence and power in the Middle East, drawing on religious and political divisions.